1. Field of the Invention
An embodiment of the present invention relates to a technique for selectively forming a semiconductor layer over a substrate, or a technique for selectively forming an integrated circuit, an active element, a passive element, or the like which is formed by using the semiconductor layer, over a substrate.
2. Description of the Related Art
In today's electronics industry, a technique for attaching or mounting an integrated circuit, an active element, a passive element, or the like, or a substrate chip (hereinafter referred to as a chip) including any of these or a device (a package) in which the chip is sealed in plastic, ceramics, or the like on a substrate is essential. Hereinafter, a “chip” in this specification is not limited in size, thickness, and shape, unless otherwise specified. This technique is needed, for example, when an LSI chip or an LSI package used for driving an active matrix circuit is attached on a glass substrate provided with the active matrix circuit. For example, COG and TAB are known as a technique for attaching an LSI chip and a technique for attaching an LSI package, respectively.
However, when an LSI chip or an LSI package is attached on a substrate with such a technique, the thickness is increased in a portion where the attachment is performed. As a method for solving this problem, there is a technique in which a chip or the like is attached on a substrate and then separation is performed so that only a surface portion where a circuit is formed is left on the substrate, whereby the thickness is reduced, as disclosed in Patent Document 1 (see Patent Document 1).
The following technique is also disclosed. A surface of a region of a substrate, where a chip or the like is to be placed, is made hydrophilic and a surface of the other region is made hydrophobic. Further, a surface of the chip or the like, which is to be in contact with the substrate, is also made hydrophilic. A proper quantity of liquid is dropped onto the hydrophilic region of the substrate, and then the chip or the like is roughly dropped to the portion where it is to be placed. Consequently, the position of the chip or the like is precisely aligned in a self-aligned manner by surface tension of the liquid (see Patent Document 2 as an example).